Minimization of drive tests (MDT) is a technology in which a network and/or a user equipment (UE) automatically collects a measurement result to assist with network problem analysis, to reduce the workload of drive testing.
In a wireless network, network entities involved in the MDT include:
1. an MDT trigger device: a device triggering an MDT process, which is responsible for starting the MDT, and may be a wireless network management device, for example, an operation and maintenance center (OMC), or a core network;
2. an MDT execution device: a device executing MDT measurement, which may be a base station or UE. If it is UE, the UE reports an MDT measurement result to a base station or a base station controller, and then the base station or the base station controller forwards the MDT measurement result to a trace collection entity (TCE); and
3. the trace collection entity TCE: receiving the MDT measurement result.
A general MDT measurement process is shown in FIG. 1. An MDT trigger device sends MDT activation message to a base station or a base station controller. After receiving the MDT activation message, the base station or the base station controller executes MDT measurement; or determines that measurement needs to be executed by UE, and sends a measurement configuration message to the UE. After receiving the measurement configuration message, the UE performs MDT measurement, and reports a measurement result to the base station or the base station controller. The base station or the base station controller reports, to a TCE, an MDT measurement result obtained by the base station or the base station controller through the measurement or the collected MDT measurement result obtained by the UE through the measurement.
In the existing MDT technology, there may be several measurement types as follows:
1. signal level measurement: UE measures a signal level of a wireless signal and reports a measurement result to a base station or a base station controller, and then the base station or the base station controller reports the measurement result to a TCE;
2. QoS measurement: generally a base station executes the QoS measurement (for example, service traffic, a service throughput, or a service delay), where the measurement may be performed at a radio access bearer (RAB) level or a UE level; and
3. accessibility measurement: UE records information about a radio resource control (RRC) establishment failure, and reports the information to a base station or a base station controller, and then the base station or the base station controller reports the information to a TCE.
At present, there is a multi-station transmission technology, that is, multiple service stations are aggregated to transmit data for one UE. The service stations herein may be a base station and a base station controller (for a 2G or 3G mobile communications system), or only base stations (for a 4G communications system). The multi-station transmission technology includes but is not limited to: uplink boosting (UL boosting) in a Universal Mobile Telecommunications System-Long Term Evolution (Universal Mobile Telecommunications System-UMTS-LTE) station aggregation transmission technology (as shown in FIG. 2A), small cell enhancement (Small Cell Enhancement, SCE) in an evolved NodeB (Evolved NodeB, ENB)-ENB station aggregation transmission technology (as shown in FIG. 2B), a multi-flow (multi-flow) transmission technology (as shown in FIG. 2C) in a UMTS NodeB (NodeB)-NodeB aggregation transmission technology, and the like.
In the multi-station transmission technology, generally the multiple service stations are classified into a primary station and one or more secondary stations. A case that may occur includes but is not limited to: all service stations in the multiple service stations simultaneously transmit data packets for UE; some service stations in the multiple service stations transmit data packets for UE; all service stations in the multiple service stations simultaneously transmit data packets of a same service (for example, a same RAB) of UE; and different stations in the multiple service stations respectively transmit data packets of different services (for example, different RABs).
Existing MDT technologies are all technologies applied to transmission between UE and a single service station. In a multi-station transmission scenario in which UE simultaneously transmits data packets for multiple service stations, there is no method for implementing MDT measurement.